Double patterning method using tilt-angle deposition

ABSTRACT

Methods for patterning material layers, which may be implemented in forming integrated circuit device features, are disclosed. In an example, a method includes forming a first resist layer over a material layer; forming a second resist layer over the first resist layer; forming an opening that extends through the second resist layer and the first resist layer to expose the material layer, wherein the opening has a substantially constant width in the second resist layer and a tapered width in the first resist layer; and performing a tilt-angle deposition process to form a feature over the exposed material layer.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced rapidgrowth. In the course of IC evolution, functional density (i.e., thenumber of interconnected devices per chip area) has generally increasedwhile geometry size (i.e., the smallest component (or line) that can becreated using a fabrication process) has decreased. This scaling downprocess generally provides benefits by increasing production efficiencyand lowering associated costs. Such scaling down has also increased thecomplexity of processing and manufacturing ICs and, for these advancesto be realized, similar developments in IC manufacturing are needed. Forexample, as geometry sizes shrink, conventional patterning processes(such as conventional photolithography processes) have difficultyforming IC features having small geometry sizes, particularly astechnology nodes continue evolving to 20 nm and below. As a result,double patterning, extreme ultraviolet (EUV), and electron beam writingmethods have been implemented to achieve these smaller geometry sizes.However, such methods introduce significant increase in manufacturingcosts, and in some cases, significant increase in manufacturingprocesses (and thus manufacturing time). Accordingly, although existingIC patterning methods approaches have been generally adequate for theirintended purposes, they have not been entirely satisfactory in allrespects.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale and are used for illustration purposesonly. In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 is a flow chart of a method for fabricating a patterned materiallayer according to an embodiment of the present disclosure.

FIGS. 2-9 and FIGS. 10A-10B are various diagrammatic cross-sectionalviews of various embodiments of an integrated circuit device duringvarious fabrication stages according to the method of FIG. 1.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

FIG. 1 is a flow chart of an embodiment of a method 100 for fabricatingan integrated circuit device feature according to various aspects of thepresent disclosure. The method 100 begins at block 110 where a firstresist layer is formed over a material layer. At block 120, a secondresist layer is formed over the first resist layer. At block 130, anopening is formed that extends through the second resist layer and thefirst resist layer to expose the material layer. The opening has asubstantially constant width in the second resist layer and a taperedwidth in the second resist layer. In an example, the first resist layerand the second resist layer form a resist layer having an undercutprofile. At block 140, a feature is formed over the exposed materiallayer using a tilt-angle deposition process. In an example, at least twotilt-angle deposition processes form a patterned layer over the materiallayer. In another example, the feature is a patterned hard mask layerthat is used to etch the material layer to form the integrated circuitdevice feature. In another example, the feature may be the integratedcircuit device feature, such as a layer of a gate stack formed over asubstrate (the material layer) or a contact formed over the materiallayer. The method 100 may continue at block 150 to complete fabricationof the integrated circuit device. For example, the first resist layerand the second resist layer may be subsequently removed by a suitableprocess, such as a lift-off process. Thereafter, where the feature is apatterned hard mask layer, the patterned hard mask layer is used to etchthe material layer to form the integrated circuit device feature, suchas a gate stack or a contact. Additional steps can be provided before,during, and after the method 100, and some of the steps described can bereplaced, eliminated, or moved around for additional embodiments of themethod. The discussion that follows illustrates various embodiments ofan integrated circuit device that can be fabricated according to themethod 100 of FIG. 1.

FIGS. 2-10 are various diagrammatic cross-sectional views of variousembodiments of an integrated circuit device 200 during variousfabrication stages according to the method 100 of FIG. 1. FIGS. 2-10have been simplified for the sake of clarity to better understand theinventive concepts of the present disclosure. Additional features can beadded in the integrated circuit device 200, and some of the featuresdescribed below can be replaced or eliminated for additional embodimentsof the integrated circuit device 200.

In FIG. 2, a substrate 210 is provided. In the depicted embodiment, thesubstrate 210 is a semiconductor substrate including silicon.Alternatively or additionally, the substrate 210 comprises anotherelementary semiconductor, such as germanium; a compound semiconductorincluding silicon carbide, gallium arsenic, gallium phosphide, indiumphosphide, indium arsenide, and/or indium antimonide; an alloysemiconductor including SiGe, GaAsP, AlinAs, AlGaAs, GaInAs, GaInP,and/or GaInAsP; or combinations thereof. In yet another alternative, thesubstrate 210 is a semiconductor on insulator (SOI). In otheralternatives, semiconductor substrate 210 may include a doped epi layer,a gradient semiconductor layer, and/or a semiconductor layer overlyinganother semiconductor layer of a different type, such as a silicon layeron a silicon germanium layer. Alternatively, the substrate 210 mayinclude a non-semiconductor material, such as a glass substrate forthin-film-transistor liquid crystal display (TFT-LCD) devices, or fusedquartz or calcium fluoride for a photomask (mask). The substrate 210 mayalternatively be referred to as a material layer, or the substrate 210may include a material layer upon which features will be formed or inwhich a pattern will be transferred (for example, by etching) to formfeatures of the integrated circuit device 200. In an example, thematerial layer is a metal layer, a semiconductor layer, or a dielectriclayer. In another example, the material layer is a hard mask layer, suchas a silicon oxide layer or a silicon nitride layer.

A resist layer 220 is disposed over the substrate 210, and a resistlayer 230 is disposed over the resist layer 220. The resist layers 220and 230 may also be referred to as photoresist layers, photosensitivelayers, imaging layers, patterning layers, or radiation sensitivelayers. The resist layers 220 and 230 are formed over the substrate 210by a suitable process, for example, by a spin-coating technique, whichmay include baking each resist layer 220 and 230 after coating. Theresist layers 220 and 230 may include positive-type or negative-typeresist materials. The resist layer 220 and the resist layer 230 includematerials that are configured to achieve an undercut profile afterpatterning the resist layers 220 and 230, as discussed further below. Inthe depicted embodiment, the resist layer 220 is configured as anundercut resist layer, and the resist layer 230 is configured as awindow-open resist layer. For example, the resist layer 220 and theresist layer 230 include poly(methylmethacrylate) (PMMA) in varyingconcentration levels, such as the resist layer 220 having a PMMAconcentration of less than or equal to about 2% and the resist layer 230having a PMMA concentration of about 4% to about 6%. In an example, theresist layer 220 and/or the resist layer 230 may have a multi-layerstructure. The resist layers 220 and 230 have any suitable thickness.For example, the resist layer 220 has a thickness of about 100nanometers (nm) to about 3,000 nm, and the resist layer 230 has athickness of about 100 nm to about 5,000 nm. One or more antireflectivelayers, such as top antireflective coating (TARC) layers or bottomantireflective (BARC) layers, may be disposed between the substrate 210and the resist layer 220, between the resist layer 220 and the resistlayer 230, over the resist layer 230, or a combination thereof.

In FIGS. 3 and 4, the resist layers 220 and 230 are patterned to form apatterned resist layer having at least one opening therein. In FIG. 3,the resist layer 230 is subjected to an exposure process 240. Forexample, the resist layer 230 is exposed to a radiation energy, such asultraviolet (UV) radiation, through a mask (photomask or reticle) havinga predefined pattern, resulting in a resist pattern that includesexposed regions of the resist layer 230, such as exposed portions 242.The radiation energy may use a 248 nm beam by krypton fluoride (KrF)excimer laser or a 193 nm beam by argon fluoride (ArF) excimer laser.Thereafter, the resist layer 230 may be subjected to a post-exposurebake (PEB) process.

In FIG. 4, the resist layer 230 is developed by a suitable process. Forexample, the resist layer 230 is exposed to a developing solution, suchas tetramethylammonium hydroxide (TMAH), to remove portions of theresist layer 230. Any concentration level of TMAH developer solution isutilized depending on characteristics of the resist layer 230, such asapproximately 2.38% TMAH developer solution. In the depicted embodiment,the developing solution removes the exposed portions 242 of the resistlayer 230 and etches the underlying resist layer 220 to form openings250 that extend through the resist layers 220 and 230. Alternatively,the developing solution may remove the unexposed portions of the resistlayer 230. The openings 250 extend through the resist layer 230 and theresist layer 220 to expose the substrate 210. In the depictedembodiment, as noted above, the materials of the resist layers 220 and230 are configured to achieve an undercut profile in the patternedresist layers 220 and 230, and thus, the openings 250 have portions 252and 254. The portions 252 have a substantially constant or uniformwidth, and the portions 254 have a tapered width. Thereafter, a rinsingprocess, such as a de-ionized (DI) water rinse, may be performed.

In the depicted embodiment, as described above, two resist layers(resist layer 220 and resist layer 230) are exposed and developed toachieve openings 250 that expose the substrate 210, where the openings250 include portion 252 (a top vertical portion or “window open”portion) and portion 254 (a bottom undercut portion or “undercut”portion). Alternatively, the resist layers 220 and 230, which havevarying PMMA concentrations in the present example, are subjected toelectron-beam (e-beam) lithography to form the openings 250. In yetanother alternative, a single resist layer (not separate resist layers)is exposed and developed, similar to that described above, to achieveopenings having a window open portion and an undercut portion. Forexample, the single resist layer includes photoacid generator, and bycontrolling (or tuning) the lithography processes, photoacid generationis controlled (tuned) to obtain exposure areas in the resist layer thathave profiles with a window open portion and an undercut portion, suchthat when the single resist layer is developed, openings in the singleresist layer are similar to openings 250. In an example, changing adepth of focus and/or baking recipe (such as a soft baking recipe)controls photoacid generation to achieve openings substantially similarto openings 250. In yet another alternative, more than two resist layersmay be used to achieve the profile of the openings 250. Thus, anylithography process that achieves openings having a window open portionand an undercut portion may be used to achieve the openings 250.

In FIG. 5, a tilt-angle deposition process forms features over theexposed substrate 210. For example, a first tilt-angle depositionprocess 260 forms features 262 over the exposed portions of thesubstrate 210, and a second tilt-angle deposition process 265 formsfeatures 266 over the exposed portions of the substrate 210. In thedepicted embodiment, the first and second tilt-angle depositionprocesses 260 and 265 are physical vapor deposition (PVD) processes. Inan example, the PVD process is a sputtering process that implements acollimator. The collimator is positioned between a sputter target andthe substrate 210 (having the resist layers 220 and 230 disposedthereover), such that the collimator is a distance from the substrate210. For example, the distance from the collimator to the substrate 210is less than an atomic (or molecular) mean free path of materialdeposited during the sputtering process. In another example, the PVDprocess is a thermal evaporation process.

The first tilt-angle deposition process 260 is performed at a tilt angleα, and the second tilt-angle deposition process 265 is performed at atilt angle β. The tilt angles α and β are achieved by rotating asubstrate holder that the substrate 210 is disposed over. In thedepicted embodiment, the tilt-angle deposition processes 260 and 265deposit a same material, and thus, the features 262 and 266 include asame material. For example, the tilt-angle deposition processes 260 and265 deposit a hard mask material (such as silicon nitride, siliconoxynitride, silicon carbide, other suitable hard mask material, orcombination thereof), and thus, the features 262 and 266 form apatterned hard mask layer over the substrate 210. The tilt-angledeposition processes 260 and 265 may deposit other materials, such thatthe features 262 and 266 form a pattern of integrated circuit devicefeatures over the substrate 210. Alternatively, the tilt-angledeposition processes 260 and 265 deposit different materials, such thata material of features 262 is different than a material of features 266.

In FIGS. 6A-6C, the resist layers 220 and 230 are removed by a suitableprocess, such as a lift-off process, leaving a patterned material layer(features 262 and features 266) over the substrate 210. In an example,the various patterned material layers (including features 262 andfeatures 266) form patterned hard mask layers that are used as masks toetch the substrate 210 that is not covered by the patterned hard masklayers. The substrate 210 may be etched using the patterned hard masklayers to form integrated circuit device features, such as gates,contacts, or other suitable integrated device features. In anotherexample, the various patterned material layers (including features 262and features 266) form integrated circuit features, such as dielectricor metal features, of the integrated circuit device 200.

Each of FIGS. 6A-6C illustrate how the tilt angles α and β of thetilt-angle deposition processes 260 and 265, respectively, can be variedto adjust a pitch between the features 262 and features 266 within eachopening 250, and a width of the features 262 and 266. After thetilt-angle deposition processes 260 and 265, the features 262 have awidth, W₁, and the features 266 have a width, W₂. In FIG. 6A, using asame tilt angle for the tilt-angle deposition processes 260 and 265(α=β), the features 262 and the features 266 have equal widths (W₁=W₂);a pitch, P₁, is between a first set of features 262 and 266 and a secondset of features 262 and 266; and a pitch, P₂, is between a feature 262and a feature 266 within each opening 250. In FIG. 6B, when tilt-angledeposition process 265 uses a smaller tilt angle than tilt-angledeposition process 265 (α>β), the width of features 262 is smaller thanthe width of features 266 (W₁<W₂); a pitch, P₁, is smaller than thepitch, P₁, achieved when using the same tilt angle for both tilt-angledeposition processes 260 and 265; and a pitch, P₂, is larger than thepitch P₂, achieved when using the same tilt angle for both tilt-angledeposition processes 260 and 265. In FIG. 6C, using a same tilt anglefor the deposition processes (α=β), but the tilt angle being smallerthan that used in FIG. 6A, the features 262 and the features 266 haveequal widths (W₁=W₂) that are greater than the widths of the features262 and 266 in FIG. 6A; a pitch, P₁, is greater than the pitch, P₁, inFIG. 6A; and a pitch, P₂, is less than the pitch P₂, in FIG. 6A. Thethicknesses of the resist layers 220 and 230 and widths of the openings250 may also be varied to adjust the width and pitch of the features 262and the features. Accordingly, tilt angle, thickness of resist layers,and widths of the openings within the patterned resist layers may bevaried to achieve various sizes and pitches of patterned materiallayers.

FIGS. 7-9 illustrate various deposition processes that can be performedto form various patterned material layers over the substrate 210. Forexample, in FIG. 7, tilt-angle deposition processes 260 and 265 areperformed to form features 262 and 266 over the exposed substrate 210 inone of the openings 250; and a deposition process 270 (where a tiltangle is 0°) is performed to form feature 272. The tilt-angle depositionprocesses 260, 265, and 270 may deposit same or different materialsdepending on the desired features or patterned material layer. In anexample, the features 262, 266, and 272 include the same material. Inanother example, the features 262 and 266 include a same material, andthe feature 272 includes a material different than the features 262 and266. In yet another example, each of the features 262, 266, and 272include a different material. In FIGS. 8 and 9, the deposition processes260, 265, and 270 are used to achieve varying configurations of features262, 266, and 272. For example, in FIG., 8, the tilt-angle depositionprocesses 260 and 265 form features 262 and features 266 over theexposed portions of the substrate 210, respectively; and then, thedeposition process 270 forms the features 272 over the features 262 andfeatures 266. In another example, in FIG. 9, first, the depositionprocess 270 forms the features 272 over the exposed portions of thesubstrate 210; and then, the tilt-angle deposition processes 260 and 265form the features 262 and the features 266, respectively, over thefeatures 272. In FIGS. 8 and 9, the deposition processes 260, 265, and270 may deposit same or different materials to achieve variousconfigurations of the materials of the features 262, 266, and 272.

FIGS. 10A-10B illustrate how the tilt-angle deposition processes 260 and265 can be used to narrow a width of a window for depositing a patternedmaterial layer. In FIG. 10A, a tilt angle of the tilt-angle depositionprocesses 260 and 265 is enlarged to ensure that material is depositedon sidewalls of the openings 250, and not over the exposed portions ofthe substrate 210. The material deposited by the tilt-angle depositionprocesses 260 and 265 narrows a window of the openings 250. Thereafter,in FIG. 10B, the deposition process 270 forms features 276 over theexposed portions of the substrate 210. Because the tilt-angle depositionprocesses 260 and 265 narrow the window of the openings 250, thefeatures 276 have a narrower width than an original width (consistentwith a width of the window of the openings 250) that would have beenachieved without first narrowing the window of the openings.

Using the tilt-angle deposition processes, such as tilt-angle depositionprocesses 260, 265, and 270, in the foregoing patterning of variousfeatures extends use of conventional lithography processes (such asthose used in 40 nm technology nodes and above) to next generationtechnology nodes, particularly to 20 nm technology nodes and below. Forexample, patterning using the tilt-angle deposition processes canachieve feature sizes desired for 20 nm technology nodes and below (suchas 20 nm line widths) while using processing typically associated withgreater than 20 nm technology nodes. Accordingly, desired feature sizescan be achieved without using costly approaches, such as extremeultraviolet (EUV) patterning methods and/or electron-beam (e-beam)patterning methods. Further, using tilt-angle deposition processes canprovide patterning free of diffraction effects, which arise whenconventional lithography processes are used to form the smaller devicefeatures necessary in 20 nm technology nodes and below.

The present disclosure provides for many different embodiments. In anexample, a method includes forming a first resist layer over a materiallayer; forming a second resist layer over the first resist layer;forming an opening that extends through the second resist layer and thefirst resist layer to expose the material layer, wherein the opening hasa substantially constant width in the second resist layer and a taperedwidth in the first resist layer; and performing a tilt-angle depositionprocess to form a feature over the exposed material layer. Performingthe tilt angle deposition process includes performing a first tilt-angledeposition process at a first angle to form a first feature over theexposed material layer, and performing a second tilt-angle depositionprocess at a second angle to form a second feature over the exposedmaterial layer. The first angle and the second angle may be adjusted toachieve a desired width for the first feature and a desired width forthe second feature, and/or a desired pitch between the first feature andthe second feature.

In an example, the first tilt-angle deposition process deposits a firstmaterial, and the second tilt-angle deposition process at the secondangle to form the second feature includes depositing a second material.The deposited first and second materials may form a patterned hard masklayer over the exposed material layer. The method may further includeusing a lift-off process to remove the first resist layer and the secondresist layer. The method may further include using the feature as a maskto etch the material layer. The method may further including performinga deposition process to form another feature over the exposed materiallayer. The material layer may be positioned on a substrate holder, andperforming the tilt-angle deposition process may includes rotating thesubstrate holder to achieve a tilt angle for the tilt-angle depositionprocess.

In another example, a method includes forming a photoresist layer over amaterial layer; performing a lithography process on the photoresistlayer to form an opening in the photoresist layer that exposes thematerial layer, the opening having an undercut profile; and forming afeature over the exposed material layer, wherein the forming the featureincludes performing at least two tilt-angle deposition processes. Thefeature may be a patterned hard mask layer. To achieve a desired sizeand pitch of the patterned hard mask layer, the method may includevarying one of a thickness of the photoresist layer, a width of theopening in the photoresist layer, and a tilt angle of each of the atleast two tilt-angle deposition processes. The method further includesremoving the photoresist layer; and using the patterned hard mask layerto etch the material layer.

In one example, forming the feature over the exposed material layerincludes performing a first tilt-angle deposition process and a secondtilt-angle deposition process, wherein the first tilt-angle depositionprocess and the second tilt-angle deposition process narrow the openingin the photoresist layer; and after performing the first tilt-angledeposition process and the second tilt-angle deposition process,performing a deposition process to form the feature over the exposedmaterial layer. In another example, forming the feature over the exposedmaterial layer includes performing a first tilt-angle deposition processat a first angle to form a first feature over the exposed materiallayer, and performing a second tilt-angle deposition process at a secondangle to form a second feature over the exposed material layer. Adeposition process may also be performed to form a third feature overthe exposed material layer.

In yet another example, a method includes forming an undercutphotoresist layer over a material layer; forming a window-openedphotoresist layer over the undercut photoresist layer; forming anopening that extends through the window-opened photoresist layer and theundercut photoresist layer to expose the material layer; performing afirst tilt-angle deposition process at a first angle to form a firstfeature over the exposed material layer; performing a second tilt-angledeposition process at a second angle to form a second feature over theexposed material layer; and after performing the first tilt-angledeposition process and the second tilt-angle deposition processes,removing the window-opened photoresist layer and the undercutphotoresist layer. Performing the first tilt-angle deposition processand the second tilt-angle deposition may include forming a patternedhard mask layer over the material layer. The method may use thepatterned hard mask layer to etch the material layer.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

1. A method comprising: forming a first resist layer over a materiallayer; forming a second resist layer over the first resist layer;forming an opening that extends through the second resist layer and thefirst resist layer to expose the material layer, wherein the opening hasa substantially constant width in the second resist layer and a taperedwidth in the first resist layer; and performing a tilt-angle depositionprocess to form a feature over the exposed material layer.
 2. The methodof claim 1 wherein the performing the tilt angle deposition processincludes: performing a first tilt-angle deposition process at a firstangle to form a first feature over the exposed material layer; andperforming a second tilt-angle deposition process at a second angle toform a second feature over the exposed material layer.
 3. The method ofclaim 2 wherein the performing the first tilt-angle deposition processat the first angle and the performing the second tilt-angle depositionprocess at the second angle includes adjusting the first angle and thesecond angle to achieve a first desired width for the first feature anda second desired width for the second feature.
 4. The method of claim 2wherein the performing the first-tilt angle deposition process at thefirst angle and the performing the second-tilt angle deposition processat the second angle includes adjusting the first angle and the secondangle to achieve a desired pitch between the first feature and thesecond feature.
 5. The method of claim 2 wherein: the performing thefirst tilt-angle deposition process at the first angle to form the firstfeature includes depositing a first material; and the performing thesecond tilt-angle deposition process at the second angle to form thesecond feature includes depositing a second material.
 6. The method ofclaim 5 wherein the depositing the first material and the secondmaterial includes depositing a patterned hard mask layer over theexposed material layer.
 7. The method of claim 1 further including usinga lift-off process to remove the first resist layer and the secondresist layer.
 8. The method of claim 7 further including using thefeature as a mask to etch the material layer.
 9. The method of claim 2further including performing a deposition process to form anotherfeature over the exposed material layer.
 10. The method of claim 1wherein: the material layer is positioned on a substrate holder; and theperforming the tilt-angle deposition process includes rotating thesubstrate holder to achieve a tilt angle for the tilt-angle depositionprocess.
 11. A method comprising: forming a photoresist layer over amaterial layer; performing a lithography process on the photoresistlayer to form an opening in the photoresist layer that exposes thematerial layer, the opening having an undercut profile; and forming afeature over the exposed material layer, wherein the forming the featureincludes performing at least two tilt-angle deposition processes. 12.The method of claim 11 wherein the forming the feature over the exposedmaterial layer, wherein the forming the feature includes performing atleast two tilt-angle deposition processes, includes forming a patternedhard mask layer over the exposed material layer.
 13. The method of claim12 further including varying one of a thickness of the photoresistlayer, a width of the opening in the photoresist layer, and a tilt angleof each of the at least two tilt-angle deposition processes to achieve adesired size and pitch of the patterned hard mask layer.
 14. The methodof claim 12 further including: removing the photoresist layer; and usingthe patterned hard mask layer to etch the material layer.
 15. The methodof claim 11 wherein the forming the feature over the exposed materiallayer, wherein the forming the feature includes performing at least twotilt-angle deposition processes, includes: performing a first tilt-angledeposition process and a second tilt-angle deposition process, whereinthe first tilt-angle deposition process and the second tilt-angledeposition process narrow the opening in the photoresist layer; andafter performing the first tilt-angle deposition process and the secondtilt-angle deposition process, performing a deposition process to formthe feature over the exposed material layer.
 16. The method of claim 11wherein the forming the feature over the exposed material layer, whereinthe forming the feature includes performing at least two tilt-angledeposition processes, includes: performing a first tilt-angle depositionprocess at a first angle to form a first feature over the exposedmaterial layer; and performing a second tilt-angle deposition process ata second angle to form a second feature over the exposed material layer.17. The method of claim 16 wherein the forming the feature over theexposed material layer further includes performing a deposition processto form a third feature over the exposed material layer.
 18. A methodcomprising: forming an undercut photoresist layer over a material layer;forming a window-opened photoresist layer over the undercut photoresistlayer; forming an opening that extends through the window-openedphotoresist layer and the undercut photoresist layer to expose thematerial layer; performing a first tilt-angle deposition process at afirst angle to form a first feature over the exposed material layer;performing a second tilt-angle deposition process at a second angle toform a second feature over the exposed material layer; and afterperforming the first tilt-angle deposition process and the secondtilt-angle deposition processes, removing the window-opened photoresistlayer and the undercut photoresist layer.
 19. The method of claim 18wherein the performing the first tilt-angle deposition process at thefirst angle to form the first feature over the exposed material layerand the performing the second tilt-angle deposition process at thesecond angle to form the second feature over the exposed material layerincludes forming a patterned hard mask layer over the material layer.20. The method of claim 19 further including using the patterned hardmask layer to etch the material layer.